Yohei Michitsuji

Running performance of power-steering railway bogie with independently rotating wheels

This article proposes the concept of a steering bogie which utilizes self-steering ability while realizing further running performance with slight active control on a tight curve. An independently rotating wheel with EEF bogie naturally has self-steering ability, making use of gravity stiffness aroused by nonlinear tread gradient, but has oscillation in the wheel-steering motion. The proposed power-steering railway bogie consists of independently rotating wheels with a power-steering device and enables us to eliminate steering vibration while realizing ideal steering with slight power assist on curving. In this article, the theoretical investigation of the power-steering bogie and the control strategies is mentioned. Experimental results and numerical simulations with a scaled model vehicle show the effectiveness of the proposed bogie design and the proposed power-steering control.

Continuous observation of wheel/rail contact forces in curved track and theoretical considerations

By using non-contact gap sensors equipped on non-rotating parts of a bogie, a new measuring method of wheel/rail contact forces has been developed. The developed system has been verified to have sufficient durability for continuous measurement on in-service trains and sufficient practical accuracy after various stand tests and train running tests. After a long-period of continuous measurement on a commercial subway line, some important characteristics of wheel/rail contact mechanics were found by the analysis of measured data. Numerical simulations of curving with a full vehicle model using multi-body dynamics software were carried out, and according to the comparison with measured data, simulation results agree well with measured data in the steady-state values of derailment coefficients considering friction coefficient.

Curving performance evaluation for active-bogie-steering bogie with multibody dynamics simulation and experiment on test stand

The authors propose a new concept of the active steering bogie, which has simple mechanism and high curving performance. Active-bogie-steering bogie has the steering mechanism only between car-body and bogie frame and no mechanism in wheelsets. On curved track, the bogie frames are steered towards radial steering direction by actuators according to active control law. In this paper, we show that the lateral contact force of the leading-outside wheel can be reduced to zero even on very sharp curve by this mechanism. Validity tests were carried out by using a full-size test bogie on the rolling test stand, which can simulate curve-running condition. Bogie parameters and steering actuator characteristics are identified in order to compare the experimental results with multibody dynamics simulation. After these stand tests and simulation, we successfully verified the effectiveness of the proposed bogie mechanism and control.

Self-steering ability of the proposed new concept of independently rotating wheels using inverse tread conicity

This paper proposes the use of independently rotating wheels with inverse tread conicity to get self-steering ability without any complex bogie structure. The effectiveness of the vehicle with two single-axle bogies that use two independently rotating wheel units with inverse tread conicity is proved by the 1/10 scale model experiment. The full vehicle model is made by means of multibody dynamics software SIMPACKTM. Both the experiment and simulation results show that the proposed inverse tread with independently rotating wheels have good performance. Running stability and curving ability of the proposed inverse tread for independently rotating wheels can be realised by using the semi-active yaw damper.

Vehicle Side Slip Angle Estimation Methodology Using a Drive Recorder

In this paper we describe a side slip angle estimation methodology especially for a drive recorder which has limited vehicle sensing information. The drive recorder has attracted the attention of many researchers recently since its captured data contains valuable information that can enhance traffic safety. As the current algorithm of video capture and data acquisition, it detects hard braking by using acceleration sensor values and records the video image and vehicle data in that situation. However, the conventional trigger algorithm cannot be activated and the data cannot be recorded when the vehicle is in a side slip situation on a low friction road with low acceleration. We propose an estimation method of the vehicle side slip angle which uses lateral acceleration, yaw rate and velocity without requiring information about the steering wheel angle for the drive recorder configuration. In this paper we describe a synthesis of the estimation method based on a two-wheel lateral vehicle dynamics model and validation of the proposed methodology by experiments using an actual vehicle.

Analysis of Driver Behavior during Yellow Traffic Signals using Drive Recorder

It is necessary to examine the driver behavior in intersections since many traffic accidents occur in the area. During yellow light, drivers occasionally cause the dilemma either passing through the intersection or stopping at stop line. In this paper, using drive recorder equipped vehicle, many incident data that occurred during yellow light were investigated. Using the collected data, actual dangerous zone during yellow light was extracted. Because the zone is one of the targets for accident prevention, the obtained understandings are useful in considering measures for enhancing safety such as road-vehicle communications. For the covering abstract see ITRD E140665.

Wheel/rail friction control with feedback system detecting yaw moment of wheelset

In the subway lines of Tokyo Metro, there are many tight curves that may cause squeal noise, excessive rail/wheel wear and also rail corrugation. To solve these serious problems, an onboard friction control system has been developed by the authors and has been equipped on some commercial trains [Y. Suda, H. Komine, T. Iwasa, M. Tomeoka, K. Matsumoto, N. Ubukata, M. Tanimoto, M. Nakata, and T. Nakai, Improvement of curving performance with friction control between wheel and rail, The 17th IAVSD Symposium Poster Session, Lyngby, Denmark, August, 2001; Y. Suda, H. Komine, T. Iwasa, T. Fujii, Tomeoka, K. Matsumoto, N. Ubukata, M. Tanimoto, M. Nakata, and T. Nakai, Experiment and analysis for improvement of curving performance with friction control between wheel and rail, Veh. Syst. Dynam. 41(Suppl.) (2004), pp. 507–516.]. With the system, in order to obtain the enough effect of friction control steadily, it is natural that an appropriate quantity of friction modifier should be required [K. Matsumoto, Y. Suda, T. Fujii, H. Komine, M. Tomeoka, Y. Sato, T. Nakai, M. Tanimoto, and Y. Kishimoto, The optimum design of an onboard friction control system between wheel and rail in a railway system for improved curving negotiation, Veh. Syst. Dynam. 44(Suppl.) (2006), pp. 531–540]. On such a viewpoint, the authors propose a new friction control system with the detection of yaw moment acting on the running wheelset. In this paper, first, outline of conventional feed-forward control system is introduced; secondly, the concept of feedback friction control system is presented considering the results of the multi-body dynamics simulations, and finally some field running test results of the developed system are discussed.

Running performance of steering truck with independently rotating wheel considering traction and braking

In the EEF (single-wheel single running gear) method, the asymmetric geometry lateral force obtained by the nonlinear wheel profile makes it self-aligned to the Independent Rotation Wheelset (IRW), and lateral displacement between the wheels yaw centre and the wheel–rail contact point obtains self-steering force. But the longitudinal creep force disables these functions when traction torque is applied to the EEF wheel unit directly. In this paper, we propose a new bogie type to obtain traction force of the IRW without losing the self-alignment and the self-steering capability. Traction torque was applied to a normal IRW pair, and the front and rear joint connected steering wheels guided the traction IRW pair along the track. The running performance of the proposed steering truck was studied by numerical simulation and a scaled model experiment.

FUEL ECONOMY IMPROVEMENT OF LIGHT DUTY HYBRID TRUCK IN VEHICLE FOLLOWING SITUATION

Abstract In this paper, longitudinal vehicle dynamics of light duty hybrid truck and driver following the preceding vehicle are modeled by using experimental data of the actual target vehicle and driving simulator. Then, the problem that concerns the increase of fuel consumption is clarified by theoretical analysis using computer simulation which include both two above-mentioned models, the vehicle and the driver, as driver-vehicle system. Finally the control method of hybrid system is proposed by considering driver pedal operation characteristics to improve fuel economy in vehicle following situation.

Multibody Dynamics Simulation and Bogie Structure Evaluation for Active-Bogie Steering Truck

Railway truck is necessary to have excellent curving performance as well as high speed hunting stability, but generally they are contrary to each other. In order to realize the compatibility, many trucks with passive steering mechanism have been studied, and some of them are realized on service operation. In order to realize further improvement of bogie steering ability on sharp curve, active steering control can give effective performance, and is considered as the latest topic. As an example of the active steering bogie, the bogie with actuators between wheelsets and bogie frame is considered. The bogie mechanism realizes effective steering but requires many actuators results in complex mechanism. The truck treated here has simple but effective mechanism: Actuators are attached only between car body and truck frame. When railway trucks negotiate sharp curve running, the rolling radius difference between inside and outside wheels cannot be obtained sufficiently, and the attitude of the truck becomes so-called “insufficient steering condition”. Considering the phenomena, if the truck frame is steered by actuators toward “radial steering position of the truck”, the improvement of curving performance of the truck can be realized. This is the first concept of active-bogie-steering (ABS) truck. In this paper, detailed study and evaluation for ABS (Active-Bogie-Steering) bogie will be presented. Validity tests were carried out with the bogie on rolling test stand in NTSEL (National Traffic Safety and Environment Laboratory), which can simulate curve-running condition including transition curve. Bogie parameters and steering actuator characteristics are elaborately identified in order to compare the experimental results with multi-body dynamics simulation. According to the test results and numerical simulation, the effectiveness of the proposed bogie mechanism and control are proved.Copyright